Bariatric surgery was associated with a significant increase in the risk for intra-abdominal infections and urinary tract infections in a study published in Clinical Infectious Diseases.

In contrast, the surgery was associated with a decrease in the risk for respiratory infections and skin and soft tissue infections (SSTI).

“The observed associations were consistent across several different analytic assumptions,” the researchers wrote. “For researchers, these findings should promote further investigation into the mechanisms linking obesity and weight reduction to the risk of infectious diseases.”

The self-controlled case series study included state ED and inpatient databases from California, Florida and Nebraska. The researchers analyzed the records of 56,277 patients who underwent bariatric surgery between 2005 and 2011. The median patient age was 45 years.

The researchers analyzed the incidence of ED visits or hospitalizations due to any of four infection types — SSTI, respiratory infection, intra-abdominal infection or urinary tract infection (UTI) — after bariatric surgery, compared with a reference period of 13 to 24 months before surgery.

They found that, compared with the reference period, the risk for intra-abdominal infection at 0 to 12 months after surgery significantly increased (adjusted OR = 2.09; 95% CI, 1.78-2.46) and remained high at 13 to 24 months (aOR = 1.29; 95% CI, 1.09-1.54).

The results were similar for the risk for UTI at 0 to 12 months after surgery (aOR = 1.93; 95% CI, 1.74-2.15) and at 13 to 24 months (aOR = 1.31; 95% CI, 1.17-1.47).